The technical field generally relates to systems, methods and devices for determining air flow into an internal combustion engine and for correcting mass airflow sensor drift.
Internal combustion engines have forced induction systems that include a significant amount of plumbing for the air intake assembly prior to the air intake manifold. Mass airflow sensors are known to be employed in the air intake assembly plumbing to provide mass airflow readings that are used in engine and exhaust gas recirculation controls. Mass airflow sensors are known to be susceptible in maintaining accuracy in their output readings over the life of the engine.
The drift error in sensor readings may occur due to sensor aging, sensor contamination, or upstream plumbing changes. Algorithms have been developed for calculating and updating correction factors of a correction factor table of flow values over time when the algorithm is run at or near particular flow values of the table. While these correction techniques can be effective for relatively small changes in the drift error, their effectiveness is limited when conditions occur that cause large changes in the drift error, such as when revisions are made in the air intake plumbing or a filter is changed. In addition, these correction techniques require longer times to correct for drift error, which as a result creates larger errors in mass airflow readings and consequently less effective engine and EGR control when based on these mass airflow readings. Therefore, further technological developments are desirable in this area.